Adventures With A Brother Long Gone
by A Cup O' Joe
Summary: Yes, Sabo is dead. And, yes, he is haunting Ace. AU. Ghost!Sabo.
1. Chapter 1

**Hello! So, this idea came to me after looking at a bunch of pictures of Sabo and ASL on Instagram, and then thinking about the story How To Make An Invisible Friend (read it, it's incredibly funny but surprisingly dark when you think about it). It'll be my first actual story, so I hope you guys'll enjoy. (This is just a preview, by the way. A prolog, I guess. It's a bit (very) short.)**

"Luffy, we have to live a life with no regrets! And we'll be free!"

"Y-yeah!"

"Ace... I don't want you to die..- ow!"

"Idiot! I will _never_ die!"

Ace stood, grinning at the villagers waving at him at the docks, one person in particular waving so fast and enthusiastically it almost looked painful. Ace waved back, however, and did so until the island was but a speck in the distance.

Dropping his arm, Ace looked around the small fishing boat he was aboard. The fact that he was here out in the ocean, starting his journey, kept him excited for a little bit until he realized he hand no idea where he was going and there was nothing to do but look at the water.

Yeah, he lost interest pretty quickly.

Sighing, Ace leaned on the railing, hoping he would run into an island soon and find something interesting to do. A crew member, perhaps. Sailing alone got boring after a while.

"Bored?"

Ace jumped, startled, and got into a fighting position. Seeing no one, he faltered, shaking his head and dropping his arms to his sides. He then turned around, and-

"Boo."

"GAHH!" Ace screamed, flailing his arms and falling back on the deck. Looking back up, he saw a boy around his age sitting on a barrel, arms crossed and smirking.

Ace furrowed his eyebrows, confused for just a moment. The tail coat, cravat, and _that hat with the goggles_ was so painfully familiar and Ace was unconsciously reaching out and just hoping, _wishing_ that what he was seeing was real and not just one of those hallucinations he'd had for the longest time and just-

"S-Sa..."

"It's been a while, Ace."

 **How was it? Good start? I hope so, because I'm writing this very late at night- early in the morning, actually- and this is bound to have at least a mistake or two.**

 **I think this is kind of original, at least; I haven't seen any stories like this before. It'll be interesting to write. Also, reviews give me inspiration as well as the motivation to write more, so please review! If you do, I might cut into my very busy schedule (which actually consists of binge watching anime and reading lots of fanfiction) and write you a nice long-ish chapter. So, again, please review!**


	2. Chapter 2

"Sooo... You're a ghost?"

"Yep."

"And dead?"

"Quite."

"And you're here and grownup-ish?"

"Kind of, I guess."

The questions continued for a few more minutes, Ace staring up at the slightly translucent form of his dead brother Sabo. The latter answered patiently, waiting until the former got over the shock of seeing him.

"And-"

"Ace, I'm dead. I've died. I am deceased. Gone. You get the gist," Sabo started, smiling softly down at Ace. "It isn't the same. You're the only one who can hear me and see me, and I'm pretty sure you can't touch me. I came by, however, to say hello and a final goodbye."

Ace's eyes widened a fraction, looking up at him worriedly. "... You did? You're leaving already?" He asked shakily, biting his lip and a look in his eyes almost begging him to stay.

Sabo's mouth twitched, face an unreadable mask.

"Well then, I guess I'll just..."

Ace didn't waste a second getting up after Sabo as he stood with his back to him. Fists clenched, Ace waited a moment as Sabo turned around to face him, his eyes shadowed underneath his top hat and and blonde hair.

Taking in a deep breath, Ace spoke. "So... I guess this really is goodbye, huh?"

Sabo took a few shaky breaths, mouth twitching again. He then looked up in a deadpan.

"No, I'm haunting you for the rest of your life."

"..."

"..."

"What."

Sabo had the decency to look sheepish, scratching the back of his head. "Um. Yeah. I, uh, was... Kidding. About the, uh, goodbye thing."

Ace stood there, staring at the dead man blankly for a few seconds. Seconds turned into a few minutes, and it got uncomfortably quiet.

"Um, Ace..."

"You little _shit_!" Ace yelled angrily, lunging forward with his fist in order to punch the "living" daylights out of him. Unfortunately, Sabo was correct about Ace being unable to touch him, and he just phased right through him. Naturally, he slammed into the railing.

"I'm sorry! I'm sorry! I couldn't resist!" Sabo said, hands raised defensively. "Though, in your defense, that was kinda mean, wasn't it?"

"Dammit, Sabo, that seriously wasn't necessary."

"Sorry."

"You fuckin' better be. I would've killed you if I... Well." Ace looked at the floor, him and Sabo standing awkwardly for a second.

"Yeah."

OPOPOPOPOPOPOPOPOPOP

"Hey, Ace! Look at this!"

"What?"

It was an average day on the Grand Line. Frying a few marines, Ace falling off the ship after falling asleep, eating the ship empty, etc. You know. The usual.

"Listen to this!" Sabo said, standing in front of a wall. After making sure Ace was paying attention, he knocked on it.

"I can touch the wall! And make noises! Cool, huh? I wasn't able to do this a while ago. I guess my ghostly powers get stronger the more I practice."

Ace looked at Sabo in amusement. "That's cool an' all, but seriously? ' _Ghostly powers_ '?"

Sabo shrugged. "For lack of a better name." Glancing at something behind Ace, he pointed. "Your crew is staring at you. Again. They probably think you've gone crazy. Well, crazier than you already are, anyway."

"Oi."

One crew member in particular walked up to Ace cautiously, hands up as if to calm him down. After asking him if he was okay, and that "we're here if you ever need to talk", the crew dispersed and went to do whatever it is they did. Ace sighed, as it wasn't the first time, and Sabo's snickering behind him was starting to get a bit irritating.

Then, feeling something poke him in the back, he turned. "Wha- wait- you're _kidding_."

Sabo grinned, finger outstretched. "Interesting."

OPOPOPOPOPOPOPOPOPOP

It was snowing heavily, most crew members having a hard time climbing up the steep, icy mountain. Ace was at the front, arm raised in front of his face to block the snow. Next to him was Sabo (who, while unable to float, wasn't having as hard of a time claiming up), looking up in interest as the snow just phased through him.

He was curious. During the year that he'd been with Ace, he was slowly learning that with enough concentration and practice, he was able to physically touch things.

It all started just a month after he'd begun haunting Ace- which was really just following him around, talking and observing and making puns to drive away the boredom- when he realized he was able to lean on walls without just phasing through them. It was an exciting development, as he'd started out unable to touch anything but the floor. Only being able to touch the floor kinda sucked, too, because he couldn't make any noises while stomping or walking and wouldn't leave footprints, either. Of course, he still couldn't do that, but he could do other things, so it was just a tad bit better.

In that month, he experimented a little. While he was able to lean on the walls, he wasn't able to make any deliberate noises when focused on it. However, once, when frustrated, he punched the wall. That led to the loud sound of wood braking and the Spades had a mysterious hole in their wall for a while.

Sabo made small, almost unnoticeable improvements after that. And he knew that the longer he stayed as a ghost, he'd be able to do more. He was dead, though, so he knew that no one other than Ace would ever really be able to see and hear him speak.

It was still interesting, though.

"We're here, Cap'n!" A crew member shouted, diverting his attention away from his lingering thoughts.

Instead, he focused on Ace's grinning face as he looked at Sabo in excitement and slight nervousness, it finally being the time for him to give his thanks to someone who had taken care of their precious baby brother. Just a few meters ahead was a wide cave, a glowing fire and faint silhouettes barely visible in the thick haze of falling snow.

"Spade Pirates?"

They walked into the cave slowly and carefully, air heavy and tense as a figure spoke up from beside the fire. It was too dimly lit to make out any of their immediate features; the only thing slightly visible was a trio of scars diagonally over their left eye.

"The infamous super rookie came to _say hello_ to me?" The man says it with a smile, but the way he shifted his large sword******* and the dangerous vibes in the air was telling a different story.

Sabo nudges Ace's side lightly, urging him to respond. The latter takes a very hesitant half-step forward, then stands tall and bows deeply and elegantly with a grin. Sabo nods approvingly, swelling with pride for his student and his good manners.

"It's not what you're thinking," Ace starts. "My brother was always talking about you as his lifesaver, so I came to say thank you."

Suddenly, the man looks up with a wide, genuine smile. "You're Luffy's brother!? I didn't know that he had a brother!" At the sudden change in atmosphere, most crew members looked at Shanks and his crew with slight incredulity, as they had immediately gone from tense and on-guard to curious and grinning fondly at mere mention of the name "Luffy".

Sabo, who was also looking on with a grin, started planning the kinds of things he'd do to mess with the crew as the Yonkou announced a banquet (they were holding bottles of booze when they had arrived, and Sabo was suspecting this wasn't a rare thing.)

-Pretty Much Ten Minutes Later-

There was food, beer, and it had only been ten minutes but some people were already drunk. Of course, that meant more fun for Sabo, but that was beside the point.

Ace was sitting next to the fire with Shanks, and while their talk had been serious a few moments before, they were now trading stories about Luffy; which was hilarious, and Ace was having trouble deciding whether he wanted to laugh at the sheer stupidity or cry at it. Both happened at one point, which was even funnier, because then Ace started choking in between sob/laugh and fell into the fire. Ace was fire, though, so he was fine, but some crew members seemed disappointed for some reason.

Currently, Sabo was waiting for the moment one of the drunk pirates would stand up to get another bottle of their seemingly endless supply of alcohol. When they did, Sabo crouched down and pulled his ankle back as he went to take a step. This quickly led to tripping, falsely accusing the person behind him (who was also drunk) of tripping him, and before the person had the chance to look up at the accuser Sabo took a piece of meat and, behind the first man, threw it at the second.

As Sabo had intended, this led to a food fight. It's not like anyone was complaining, anyway.

 **Well, I hope you guys enjoyed this chapter. Sorry it took a while, but don't expect updates to come right away. Also, I know that this chapter skipped around a lot and nothing too interesting happened, but some of the stuff here will be important in later chapters. Who knows, maybe the Whitebeards will be in the next one.**

 **Oh, and thank you to my two wonderful reviewers! I had to hold back a squeal of excitement when I got them. To answer the guest's question:**

 **Yes, it will be a mix of all of that. I think. We'll see where my almost decent writing skills take this story.**

 **Thank you for reading, please leave a review!**


	3. Chapter 3

**Enjoy the chapter.**

 _There was fire. Lots and lots of fire. Everything was burning around him, the black smoke crawling into his lungs, choking him. He tried to put it out, taking off his jacket, and then wondered how this had happened so quickly._

 _He didn't have much time to elaborate on it before the sound of a cannon reached his ears, and_ _**pain, pain, pain.**_ _His boat fell apart around him, and he sunk down, down, down, drowning, trying to get air but only inhaling more and more water._

 _In his last moments, all he felt was the pain of drowning, and the pain of knowing that he wouldn't get the chance to see his brothers on the wide, blue ocean._

 _Free._

Sabo woke up suddenly and violently, clutching his chest and throat as he coughed, eyes watering.

 _I'm on the floor_ , he noticed distantly as he stood up shakily, breathing harshly and shaking his head to dispel the images of a burning boat and the deep, dark sea laid out on all sides of him.

 _ **That will not be the last time. You do not belong here, child.**_

Sabo turned around sharply, looking everywhere but unable to find the condescending voice.

 _Oh, look at that. I'm finally going insane. It only took getting to the afterlife._ Sabo thought sarcastically, dismissing the voice as unimportant.

Wishing he was still able to drink a glass of water, he felt a pair of eyes on him. There, sitting in his bed and looking up at him, was Ace. He flinched as he was spotted, before he spoke. "You okay? What happened?"

Sabo looked at him hesitantly, not knowing whether or not telling him what he dreamt of was a good idea.

"You know," he started, laughing nervously and sitting back down on the ground. "I didn't even know I could sleep. And I haven't, not a single night since I'd started traveling with you. It just sorta happened, but I don't know if I could really even call it that. It was- weird."

Ace looked at him seriously, urging Sabo to continue. He did, but his reluctance to give a direct answer was obvious. He averted his gaze.

"I had a bad dream. That's it, Ace. I'm fine, so, you can just go back to sle-"

"No." Sabo flinched, looking back up at Ace. There was a weird kind of determination in his eyes, and Sabo immediately knew he'd lost. "Tell me. I know something's wrong."

At this point, Ace just looked desperate for answers. It was almost as if he already knew what it was, but was refusing to believe it.

Sighing resignedly, Sabo looked back to the floor, biting his lip in apprehension. "I dreamt about my death."

There was a small intake of breath from Ace, and then Sabo continued; albeit with a cringe.

"Look, I'm not gonna go and make this dramatic, okay, Ace?" Sabo told Ace almost irritatedly, looking at him with narrowed eyes. He was fed up with the tension in the room, and whilst he could've made it melodramatic and sappy, he'd rather stray away from the guilt and self-loathing Ace was guaranteed to adopt after his little show.

"Alright, yeah, I'm dead. That's kind of depressing," Sabo began awkwardly, watching as Ace face-palmed; knowing that Sabo was no longer taking their conversation seriously and had moved on to something completely different. "But at the end of the day, there isn't any going back, so I'd rather dump the whole 'regretting life choices' thing than getting all sad about things that could've been. We're supposed to be living a life without regrets, aren't we?"

Sabo nodded to himself for his little speech, before adding (mostly to himself), "Well, I mean, I'm dead, so I don't actually have much of a life ahead of me."

Sabo laughed quietly to himself for a second before bidding goodnight to Ace, who had slumped back down into his bed after about five seconds of his lecture.

As Ace fell asleep, Sabo felt proud of himself for not revealing how much he really wished he was still alive.

The days went by fairly quickly after that. It wasn't too long before Sabo found himself behind a large wall of fire, shouting for Ace as the latter looked up challengingly at the strongest man in the world; Whitebeard. He was battered and tired from his five-day battle with Jinbei- a Shichibukai, as well as one of Whitebeard's friends- but still determined, nonetheless.

"Ace, you can't! He's too strong- he's the strongest man in the _world!"_ Sabo shouted, worriedly staring through the blazing fire and almost not seeing Ace get knocked back to the ground.

" _Dammit,_ " Sabo cursed, clenching his fists and hardening his resolve. Squeezing his eyes shut, Sabo braced himself and ran through the raging fire, opening his eyes when he reached the other side.

Looking down at his unharmed body, Sabo berated himself for being such a coward before he was reminded about Ace's predicament as the Yonko began to speak.

" _Gurararara..._ Cheeky brat. You're a hundred years too young to be going up against me."

Ace tried to retort, but was unable to as he leaned exhaustedly on his elbows; still half-laying on the rocks. His fire was dimming, and it was already dark outside.

"If you still want to fight... Then take my name and roam the seas, wild and free!"

Whitebeard bent down and held his hand in front of Ace. His eyes widened.

 _"Become my son."_

After that, Ace joined the crew. It was more like a different form of kidnapping, actually, and Ace was _not_ having it. It had been barely two days with Ace having refused any offers of food, staying in his little corner on the railing of the Moby Dick, and Sabo was worried.

"Ace... I know you don't trust these people, and I don't completely trust them yet, either, but you have to eat something," Sabo told Ace exasperatedly, arms crossed. Ace ignored him, purposefully avoiding his gaze. Sabo glowered at him for a moment before throwing his hands up in the air and walking away; knowing that it wasn't worth the effort and, instead, decided that exploring the ship and observing the crew members would probably do some good.

After exploring the deck some, he made it to the hallways where the living quarters were. He peaked through some doors for anything of interest before coming across the fourth division commander's room, with said commander in said room.

This particular room had caught Sabo's interest because it was the man who, throughout the day before, had frequently come to Ace to offer food. He had been fairly nice, even a bit funny, so Sabo wanted to observe a bit and see if he really is the man he was portraying.

 _'Oh, I have a great idea.'_ Sabo thought, seeing as the man (Thatch, was it?) was doing paperwork.

It was something that had worked for him before, when he was with Ace on the ship and wanted to push the limit on what he could and couldn't do.

Writing, it seemed, was one of those things he could.

So when Thatch put his quill down and began murmuring to himself about pineapples and how they shouldn't be giving people paperwork when they weren't even sentient beings (a mouthful indeed), Sabo approached his table, picked up his quill, and wrote on one of the half-blank pieces of paper that Thatch was still working on.

 **Thatch, is it? Hello, I'm Bo. Nice to meet you.**

When Sabo put the quill back where it was and looked up, Thatch was staring; dumbfounded at the sight of the new words on his important paperwork and the fact that he saw a pen writing by itself.

This lasted only a few seconds, however, before he scrambled out of his chair with the piece of paper and ran straight out the door, frantically calling for a man named Marco.

"Oops." Sabo said to himself. He didn't actually care all that much, though the reaction was fairly amusing. "I guess I'll go follow him."

He caught up to Thatch just before he ran into Marco, who was in the process of talking to Ace. Sabo jogged up to Ace, before leaning on the railing next to him. "I might've done something," He said, earning a raised eyebrow from Ace before they both looked back over to Thatch and Marco.

Thatch was waving his paper in the air in front of Marco's face, and the phoenix's eye was twitching.

"MARCO! My pen was floating in the air when I put it down because pineapples and it wrote a note on the work you gave me and _Ithinkthere'saghostontheship-"_

Thatch's startled babbling was cut off by Marco, who put a strong hand on his shoulder and looked at him irritatedly.

"Slow down, yoi. What the hell are you talking about?"

Thatch showed him the piece of paper, which Marco took and read aloud. "It says... 'Thatch, is it? Hello, I'm Bo. Nice to meet you.' ... What?"

As soon as Ace heard the name "Bo", it took all of his willpower not to look at Sabo and face-palm. He did, however, glare mercilessly at the piece of paper in the phoenix's hands.

Noticing his look, Marco turned to look at Ace curiously. "You know something, yoi?"

Ace looked towards Sabo for a moment, contemplating, before narrowing his eyes and looking the other way with a huff. "No. And if I did, it's not like I'd tell you."

Marco studied Ace at his answer, before shrugging and turning back to Thatch; returning the sheet of paper. "Here. Whatever it is, it has manners and hasn't done any harm, so I think you'll be fine. You'll have to redo that work, though."

"Dammit, and I worked so hard, too. Whatever," Thatch sighed resignedly before sullenly walking back to his room.

Marco was about to follow, before he turned back to look at Ace once more. "You know, you can eat. It's not like we're sticking any kind of poison in your food, yoi. Pops invited you onto the ship because he likes you; we have no reason to kill or hurt you. He isn't that kind of guy."

Ace stubbornly avoided his gaze. "Why do you call him 'Pops', anyway?" He scowled.

Marco smiled fondly at the question. "Because he calls us his children."

Ace finally looked over at Marco, eyebrows furrowed. Marco said nothing else, finally turning to leave. Sabo and Ace were left alone by the railing.

"Hey, Ace," Sabo called quietly. Ace turned to look at him with questioning eyes.

"I think you can trust him."

Some time passed. Ace finally accepted food, but refused to trust the Whitebeard's completely quite yet. He even tried to attack Whitebeard himself numerous times despite Sabo's insistence (utterly losing every time), but after a few months, Ace started begrudgingly warming up to the crew.

Sabo stayed around Ace most of the time, sometimes wandering around the ship to listen to the crew's lighthearted conversations and watch some pranks being pulled by Thatch and another member named Haruta. He would have tried writing more to the fourth division commander, but he and Ace both knew that it would just cause trouble, so he - although annoyed - agreed not to do it again.

Well, "never again" was a big commitment, so he wasn't going to keep to that completely. He probably wouldn't be doing it any time soon, of course.

But he would definitely be doing it again.

Back to the point, after a few months, Ace had begun to grow attached to the big crew of kind pirates. After enough time, he had officially joined the crew, and gained a huge tattoo on his back which he proudly showed off every day due to his lack of shirt. Sabo was unbelievably proud of his brother, as well, and grew to trust the pirates just as much as Ace did.

It was in the middle of a random night, both Ace and Sabo leaning on the railing next to the figurehead, when Sabo suddenly grinned at his brother; his slightly translucent form glowing slightly in the light of the moon.

"What?" Ace asked, looking at him weirdly.

Sabo's grin went soft with melancholy as he gazed up at the stars. "You've found yourself a great new family, and I can definitely say that I'm proud of you and that I trust them to take care of you if I ever have to leave."

Ace's eyes grew sad and he moved over to sit closer to his brother, sighing. "I'm glad."

They didn't say anymore, relishing the time they had together.

Later, after Ace would become second division commander, Sabo would feel something odd in the presence of a member of the second division and the fourth division commander. Something not right, something looming and eerie.

Something bad was coming. And he wouldn't know what until later.

 **Ahhhhh. I'm sorry, I'm sorry, this took way longer than it should have. And it's totally my fault, I just put off writing a lot of this due to laziness and procrastination. But I finally got to it, and out of it came a longer chapter, so I hope that makes up for it just a little. I'll try to get the chapter after this out way sooner than this one, especially with that cliffhanger at the end.**

 **Thanks for hanging in there, and thank you for the reviews on the last chapter! You have no idea how much I appreciate them.**

 **I'd love feedback! Please, leave a review!**


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